This invention relates to a computer system, and more particularly to a technique of logically partitioning a computer system including a storage system.
One approach to improving the performance of an information processing system is to increase the number of computers in an information processing system. However, the use of many computers in a system poses the following problem: it necessitates a troublesome task of controlling individual computers, requires a larger footprint for the computers and consumes more electric power.
As a solution to this problem, technology which logically partitions resources of a computer with a large processing capacity (LPAR: Logical Partitioning) and makes it possible to use resulting logical partitions as independent virtual machines has been proposed. This logical partitioning technology can make one computer look like a plurality of virtual machines. When allocation of resources (processor, memory, etc.) to partitions is controlled, the performance of each virtual machine is assured.
With this technology, different operating systems can be freely installed in virtual machines and each virtual machine can be turned on and off independently. Also faults in a virtual machine can not propagate to other virtual machines and the failed virtual machine can recover from the faults independently. Thus the computer with logical partitioning technology has greater flexibility than that of computer which does not have the technology.
In addition, the user can consolidate physical machines into fewer physical machines. As a consequence the user benefits from the logical partitioning technology in terms of system management, footprint, and power consumption. This kind of logical partitioning technology is disclosed, for example, in JP 2003-157177 A.
Also, US 2003-0055933 discloses a technique of accessing a storage system from a logically partitioned virtual machine.
Also, a storage system logically partitioned by applying a technique of logically partitioning computers is proposed in IBM, “The IBM TotalStorage DS8000 Series: Concepts and Architecture”, [online], Internet <URL: http://www.redbooks.ibm.com/redpieces/pdfs/ sg246452.pdf>.